Missed approach (?) when glideslope fails

"RK Henry" wrote in message
...
You are on an ILS approach, DH 200'. The localizer-only MDA is 500'.
You are at 300' in IMC when the GS fails. Assuming you are timing the
approach, is it legal to climb to 500 and continue the approach?

That's how I was taught. You time the ILS approach, even though it's
not necessary, in case the GS fails and you can climb to the MDA and
continue as a LOC approach. I've read several articles advising that.
I was even told that not timing the ILS approach was a failure item on
the checkride, so I did as I was taught and timed the approach. I
guess it's good practice against the possibility of forgetting to time
the approach when it really does matter.

For my IMC rating (UK-only "baby brother" of an IR) the instructor didn't
insist on timing the ILS approach, but did point out that if you've got
other aids (ADF, DME) there's no harm in having them tuned in as a
cross-reference.

D.

On Thu, 08 Sep 2005 09:56:22 +0100, Peter wrote:


Roy Smith wrote:

Consider also how inaccurate timing is. In a typical GA airplane, 100 feet
above DH on the GS is about 10 seconds away from the ILS MAP; what makes
you think your FAF-MAP timing is accurate to within 10 seconds?

This is interesting. I've been taught (FAA IR) to always time the
approach, even an ILS.

I am not sure what the point is, except in the case of a loss of GS,
on a no-DME approach.

Airline pilots I've spoken to never time anything when going down an
ILS. If they lose GS, they will go up right away.

There is no requirement to time an ILS approach in the FAA IR-PTS
(Practical Test Standards). For what it's worth, I was taught that timing
of an ILS was optional.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On Thu, 08 Sep 2005 07:32:14 -0400, Ron Rosenfeld
wrote:

On Thu, 08 Sep 2005 09:56:22 +0100, Peter wrote:


Roy Smith wrote:

Consider also how inaccurate timing is. In a typical GA airplane, 100 feet
above DH on the GS is about 10 seconds away from the ILS MAP; what makes
you think your FAF-MAP timing is accurate to within 10 seconds?

This is interesting. I've been taught (FAA IR) to always time the
approach, even an ILS.

I am not sure what the point is, except in the case of a loss of GS,
on a no-DME approach.

Airline pilots I've spoken to never time anything when going down an
ILS. If they lose GS, they will go up right away.

There is no requirement to time an ILS approach in the FAA IR-PTS
(Practical Test Standards). For what it's worth, I was taught that timing
of an ILS was optional.

I was taught to time an ILS because there are places like BED (ILS 11
or 29) where without a GPS you can't ID the missed approach point if
the glideslope fails without timing the approach.

Peter Clark wrote:

I was taught to time an ILS because there are places like BED (ILS 11
or 29) where without a GPS you can't ID the missed approach point if
the glideslope fails without timing the approach.

I can't believe people still discuss this issue. Firstly, timing an
approach takes a fraction of a second - simply push a button. Secondly, if
you time every approach it becomes part of your checklist, your routine etc.
Thirdly, as you point out, what the heck do you do (can you do) if you're in
IMC on an ILS and your GS fails? You're screwed and only luck will save
your butt (it may be less dramatic when surrounded by flatter terrain).

So, Peter, I agree with you 100% - time every approach.

Hilton

Hilton wrote:

I can't believe people still discuss this issue. Firstly, timing an
approach takes a fraction of a second - simply push a button. Secondly, if
you time every approach it becomes part of your checklist, your routine etc.
Thirdly, as you point out, what the heck do you do (can you do) if you're in
IMC on an ILS and your GS fails? You're screwed and only luck will save
your butt (it may be less dramatic when surrounded by flatter terrain).

Well, I won't disagree with you about doing the timing. Its cheap, its
easy, and it couldn't hurt.

However, if I'm on the ILS and my only GS fails, I'm going missed RIGHT
NOW. I don't care wether I have a timer or not.

Yes, of course, if I'm down to my last pint of fuel, I'm rather forced to
continue and the timer would be very useful. However, if thats the case,
I've made a whole batch of mistakes.


--
Frank Stutzman
Bonanza N494B "Hula Girl"
Hood River, OR

Frank,

Hilton wrote:

I can't believe people still discuss this issue. Firstly, timing an
approach takes a fraction of a second - simply push a button. Secondly,
if
you time every approach it becomes part of your checklist, your routine
etc.
Thirdly, as you point out, what the heck do you do (can you do) if
you're in
IMC on an ILS and your GS fails? You're screwed and only luck will save
your butt (it may be less dramatic when surrounded by flatter terrain).

Well, I won't disagree with you about doing the timing. Its cheap, its
easy, and it couldn't hurt.

However, if I'm on the ILS and my only GS fails, I'm going missed RIGHT
NOW. I don't care wether I have a timer or not.

The problem is that you have no missed approach procedure to follow. Let's
say, for example, that the missed is a 180 degree turn back to the LOM. If
you start your turn early (i.e. fly the missed right now), you may hit a
mountain.

i.e. you must have a way to determine (at least approximately) where the MAP
is; for examples are GS, DME, VOR, timing... You have to fly to the MAP to
be safe on the missed. Of course, you can and should climb if your GS dies.

Hilton

On Thu, 08 Sep 2005 16:47:24 -0400, Peter Clark
wrote:


I was taught to time an ILS because there are places like BED (ILS 11
or 29) where without a GPS you can't ID the missed approach point if
the glideslope fails without timing the approach.

I would never try to talk someone out of timing an ILS. However, I do not
find it necessary.

Yours not good examples of a need to time in order to decide when to start
executing a missed approach.

You could (and should) start your climb immediately. On the ILS 29 the
climb to the holding fix is straight ahead; so ID'ing the MAP is
irrelevant.

On the ILS 11 there is a slight turn of 5° at most, which is not going to
cause a problem. But if you are really, really concerned, and don't have a
GPS, you likely have DME and a marker beacon receiver, so you could ID the
MAP with the former, and/or start your 5° turn at the latter (perhaps after
the tone fades out).

It is of more concern where the missed approach segment is a turning
course. However, the next time you fly an ILS, watch the localizer needle
as you get close to the runway. You will find it pretty simple to note the
increased sensitivity of the needle and/or the flipping of the needle back
and forth as you pass over the station. Depending on which end of the
runway the LOC transmitter is located; and the missed approach segment;
either of these can be used to decide where/when to start your turn.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On Thu, 08 Sep 2005 21:26:17 GMT, "Hilton" wrote:

what the heck do you do (can you do) if you're in
IMC on an ILS and your GS fails? You're screwed and only luck will save
your butt

You can't be serious with that claim.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

"Hilton" wrote in message
nk.net...

Thirdly, as you point out, what the heck do you do (can you do) if you're
in
IMC on an ILS and your GS fails?


You fly the missed approach procedure.



You're screwed and only luck will save
your butt (it may be less dramatic when surrounded by flatter terrain).


Nonsense.

Steven P. McNicoll wrote:

Hilton wrote:

Thirdly, as you point out, what the heck do you do (can you do) if
you're
in
IMC on an ILS and your GS fails?


You fly the missed approach procedure.

Steven, when would you start your turn back to the LOM (or in any other
direction)?

The missed approach starts from the MAP (DH) - since you cannot ensure you
are at the MAP, you never really know you're flying the published missed -
therefore all bets are off so to speak.

The missed approach only provides protection if you fly it correctly and as
published (obviously).

Hilton


Hilton